The invention is based on a hydraulic vehicle brake system as defined hereinafter for wheel slip control.
In such hydraulic units of hydraulic vehicle brake systems, damper chambers and damper throttles are disposed downstream of pressure outlets of pumps, which are designated as return pumps or auxiliary pumps, for instance; the damper chambers and damper throttles are intended to keep pressure pulsations originating at the pressure outlets and thus pressure waves largely away from the master cylinders. As British Patent 1,590,003 teaches, the damper chamber may be embodied as a substantially cylindrical hollow chamber in the housing, with an inlet opening located in the longitudinal axis of the hollow chamber. A throttle bore, which extends radially outward substantially half-way up the length of the hollow chamber, discharges into an outlet opening. The volumetric elasticity of the pumped pressure fluid is utilized for the damping. A further damping device is integrated into a pump housing, as taught by German Offenlegungsschrift 39 24 085, and as its damping element it has a radial-elastic hollow chamber located in the extension of an inlet opening, the hollow chamber being bounded by way of example by means of a length of hose fastened at both ends in a pressure-tight manner, and a shield body forming an outlet opening in the extension of the inlet opening. The radial-elastic hollow chamber acts similarly to an air chamber. The shield body is adapted to the exciter frequency, which is proportional to the pump rpm.
The aforementioned damping devices damp the pressure pulsations originating in the pumps and accordingly also damp pressure waves, so that the applicable pump cannot cause much irritating noise in the region of the master cylinder.